Okay, time to liven up this thread with some controversial opinions.
Terraforming Mars is a good game. But I don't like it. Similarly, we got Villainous for Christmas, and we played it, and it's a good game, but I don't like it. They both fall into a gigantic category of games that I don't like, a category that includes games ranging from Magic The Gathering to Race For the Galaxy to Oath. And that category is:
Games Where You Really Need To Know What Special Rule Is On Every One Of The Hundreds Of Different Cards In The Game
I like games where you can hold the entire game, conceptually, within your head. Even if the game demands attention to intricate details, and has surprising and complex interactions between the moving pieces, I want to be able to understand how all the pieces move - what all the rules of the game are - and to be able to explain them simply and briefly and coherently. Games where the bulk of the game is actually driven by the special cases that constitute each different card simply frustrate and annoy me. You need to know all the cards; and if you
don't know the cards, then you need to read them one by one as they come into play, whether they're in your hand or your opponents', and how fun is it to ask the other players to read their cards out loud to you
especially if they already know them? No fun, that's how fun. No fun at all. And a great deal of the game is about sorting through all the different cards to find optimal combos, which is a daunting task if you don't already know what they all are, being a mostly hit-or-miss affair of making guesses on the fly.
I have a certain degree of tolerance for this kind of stuff, but the more different cards there are, and the fiddlier each card's special rule is and the more finely the rulespace is carved up into tiny differences just to have more cards, the greater the strain the game places upon my limited tolerance.
... but maybe that's just me.